Jump to content
SAU Community

Recommended Posts

ive got a cut and rewelded stock rb25 plenum on my rb25 motor. just wondering if there ok in terms of flowing evenly to all cylinders. just because i have recently done a compression test and the number 6 piston i think it is (closest to firewall) is down to 50 psi or so. the others have a fair bit of variance also.

i just wanna find out if people think thats what would have caused it or if it would have happened if it was normal style. coz ive got a rb30 twincam motor il be putting in soon but dont wanna put it in with that plenum if its gunna make the new motor do the same thing.

ive got a greedy copy plenum here also i could put in but im thinking il just use the standard one again for ease of installation coz i think the greedy one is sorta hard after looking at the guide. or is it really not that hard to put on in regards to changing a few pipes and throttle cable mounting and stuff and i should use the greedy copy one with 80mm throttle body?

this is the one in my car. would it flow evenly and stuff. the vl turbo guys have the same sorta ones and its very common for them to have it made like my one. one of the main shops even uses that sort on a 8 second drag car rb30. i think

r33skyline015.th.jpg

also, will i have the problem with the bit hitting the bonnet with this current plenum since its different? cant remember where they hit the bonnet with rb30 bottomend with rb25 head.

Link to comment
https://www.sau.com.au/forums/topic/302521-rb25-forward-facing-plenum/
Share on other sites

i did this to my r33 and added a 90mm throttle body, i actually got an extra 13rwkws and now i upgraded my turbo to a t67-25g on stock internals running 304rwkw and its fine, it improved the response also. and doest hit my bonnet but mine is just a rb25 bottom, my throttle cable also reaches

yer they used dog turds when they welded it bro

the look of the weld mainly determines the quality of the weld. In your case is slapped on there and that usually means a total lack of penetration. Sooo... it means it will crack or leak, neither of which you want to happen.

Good call on the low comp. Sort the motor before messing with plenums.

Besides that, i dunno why you'd go to the trouble of welding it up for poor flow etc. when a greddy knockoff plus a little bit of work will only set you back a few hundred bucks.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • 2 spots that my exhaust guy joined the 2 pipes together  Made a big difference. I'm now able to live with it. I can make it louder if I want by removing the HKS caps.
    • Hi all, considering clutch upgrade to support 1130 engine hp from 1650cc injectors on e50 at 85% duty cycle (1650 x (11.85/14.7) x 85%). Narrows down to these three as they can be converted to use gm 26 spline input shaft if I ever want to use transmission with that input shaft (orc1000f and r3c easy/cheap just change center hub; tr2cd pricier must change clutch discs). Pricing orc1000f similar to tr2cd, r3c about usd 200 pricier. Orc1000f triple plate 200mm. Tr2cd twin plate 215mm. R3c triple plate 215mm. Claimed max torque : orc 1000f 723 lbs ft; tr2cd 800 lbs ft; r3c 1100 lbs ft. Why orc1000f triple plate but claims lower max torque vs tr2cd twins? Is orc1000f underrated? Any info maxing out these clutches? Info on street/traffic driveability/pedal feel? Thank you for any info on them.
    • Some troubleshooting, connect up a timing light/gun with a proper ignition lead on coil 1. Hold the revs at 4~4500rpm and see if your timing is all over the shop, scattering off its tits. If so, there's a high chance your CAS is fked. But I read you have a Link ECU ready to go in, why not just skip all this and put that in - will make troubleshooting so much easier.  
    • Misfires when the car is fully warm are generally attributed to the coils (and/or the igniter, on cars with a separate igniter). They can stop working properly when they get hot for a number of reasons. Either electric/electronic, or from thermal expansion opening up gaps and allowing HV leakage. Seeing as you have replaced the coils, that could/should rule them out. But I wouldn't always assume so. Were the coils genuine? Or is there a chance you have bought some counterfeit Chinesium shit? Then we're back onto loom connections. They can fail when warm/hot for the same reasons. Inspections, cleaning of contact surfaces, ensuring that terminals are fully inserted, etc etc, are all justified. The same (heat effects) holds true for the other electrics and their connectors. AFM & CAS, primarily. If you try that Chinesium AFM, drive it around on low load until it is properly hot, but do'nt give it more load than you have to, except when you need to see if it will still miss. I'm dead serious about the untrustworthiness of the calibration of those copy AFMs. Injectors are unlikely to get hot unless the fuel is coming back around hot. You could try squirting them with compressed air or freeze spray to cool them back down to see if they are maybe the cause.
    • Alright, all the plugs looks good. Noticed that it starts to get bad when the car is up to temp, that's when things starts to misfire hard. next to do is Injector cleaning and such. Got in touch with a shop to do work on the injectors next Monday also help on diagnosis.
×
×
  • Create New...